Method of and machine for preparing molding and packing sand and like material



' Marh 5, 1940.

METHOD OF AND MACHINE FOR PREPARING H WAGNER MOLDING AND PACKING SAND AND LIKE MATERIAL Filed July 8, 1937 M II II INVf/VTOR //[//v/P/c// VIQGMER 5 Y H TTORNEYS Patented Mar. 5, 1940 METHOD AND MACHINE FOB PBEPABIN G MOLDING AND PACKING SAND AND LIKE MATERIAL Heinrich Wagner, hasphe-on-the liahn, Ger- Lahn, Germany Application In c Claims.

It is known to prepare the molding sand for use in foundries by projecting the initial material to form a stream in a projecting machine in order to separate the wanted from the unwanted ingredients. Particles of iron in the sand are, however, not separated out by this means, so that a.separate iron separator, usually an electromagnet, has been used in order to remove the iron from the molding sand either before or after it has been thrown as described. The use of the iron separator, however, has the disadvantage that the possible output of the projecting or conditioning machine is limited since the sand must pass a good'deal more slowly through the separator than through the projecting machine. In order, therefore, to obtain the same output a number of separators must be used with one projecting machine. 1 This disadvantage is obviated by the present the particles of iron is eifected in the stream of the projected sand itself. The sand is already loosened or spread out by the projectingprocess by the time it arrives at the magnet, so that even the smallest particles of iron are free from the sand particles and are, therefore, at once attracted by the magnet. Furthermore, in this process the output of the projecting machine is not reduced. One can give the sand stream .a high velocity and yet be assured that the iron particles are substantially completely'removed from it by the magnet.

The magnet is preferably so arranged that the projected sand streams are immediately underneath it. The iron particles are heavier than the sand and are, therefore, uppermost in the sand stream. If necessary separate iron fingers or lamellae can be mounted on the magnet which project into the sandstream'and remove even the somewhat more deeply suspended iron par- 'ticles.

The process is carried :out with periodical deenergisation of the magnet, when his covered with iron particles, and this can be done by switching oif the energising current or stopping the current generator which supplies the energising windings of the magnet. At the time of such de-energisation the feeding of sand tothe projecting apparatus is also interrupted. The ironparticles held by the magnet then fall, preferably into a container. The periodical de-energisation ofethe magnet can be effected by hand or automatically by any appropriate switching "device.

An example of a machine for carryinl out the tion members 6 is .flXed to the band 5.

invention, whereby the magnetic separation of assignor to Miilier und Wilmer. Modell Maschinenbau, Wallan near Biedenkopi,

July 2, 1937, Serial No. 152,548 Germany September-5, 1988 invention is illustrated by the accompanying drawing, in which:

Fig. 1 is a part longitudinal section; Fig. 2 is a plan partly in section, and Figs. 3 and 4 show alternative forms of the I electromagnet. The projecting apparatus, which consists in a known manner of two drums 3 and 4 over which runs an endless band 5 of rubber or other suitable material, is mounted on-a carriage 2 sup- 10' ported by wheels I. A large number of projec- The machine is driven by an electric motor I through a belt 8 and the drum 4. At the same time the motor also drives through a belt 9 a generator l0 l8 which generates the energising current for the electromagnet H. The latter may have the form shown in Fig. 3 or Fig. 4, and is arranged so that it lies over the sand stream projected by the belt t. The underneath pole of the magnet may or 90 may not be provided as shown in Fig. 4 with separate project ng plates l2 arranged as fingers or lamellae which project downwards into the projected sand stream. These plates when used are preferably somewhat sharpened on their front 2 edges so that the sand can flow past them with as little hindrance as possible.

The projecting band 5 forms the floor of a container I3 into which the sand to be prepared is fed either by hand or through a mechanical feed- 80 ing device. Behind the magnet II in the path of the sand there is provided, in known-manner, a hood ll which can be adjusted to deflect the sand stream downwards when it is not desired to to project it far.

Under the electromagnet II is a container it into which the separated iron fails when the magnet is de-energised. The iron may be removed from this container through a door or flap into a larger intermediate container.

The machine operates as follows. The sand to be separated is loaded into the container i3 and moves with the band i and the members 0, these members moving at high velocity in the direction of the arrow. The sand stream I6 v Q then flows under the electromagnet II and is projected a greater or less distance according to the adjustment of the hood ll- As they pass the electromagnet Ii, which is excited by the generator in. the particles of iron floating m V i0 is stopped by a suitable switching device, or the current to the magnet otherwise interrupted; so that electromagnet II is de-energised and the particles of iron thereon fall into the container i5. While the magnet is de-energis'ed it is necessary to interrupt the loading of the sand into the container I3. When the generator current is again switched on thefeeding of the sand can be re-commenced.

In certain circumstances the periodical interruption of the energising current can be effected automatically by a suitable switching device. If the energising current be permanently interrupted the machine can be used as a projecting machine operating in known manner for sand or other material free from iron particles.

The electromagnet can be located otherwise than as shown; it is essential only that the pole or fingers should reach to the sand stream.

While the projecting machine shown is provided with a projecting band, a machine can obviously be used having one or more projecting wheels or other projecting means instead of a belt.

The process and the machine can also be used for separating the iron constituents from nonmagnetic metal shavings or like material.

Having now particularly described-and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

' 1. The method of preparing sand for foundries and the like consisting of thoroughly dispersing and drying the raw sand by projecting it into the atmosphere in a free, unconfined stream in an are having an upward inclination to the hori-- atmosphere in a free, unconfined stream in an are having an upward inclination to the horizontal said are being free of any confining surfaces and magnetically detaining the iron particles adjacent the crown of said are to permit the separated sand to fall freely during the period of descent.

3. The method of preparing sand for foundries and the like consisting in thoroughly'dispersin'g and drying the sand by projecting it into the atmosphere in a free, unconfined stream in an are having an upward inclination to the horizontal said are being free of any confining surfaces and magnetically detaining the iron particles from said are during the period of ascent to permit the separated sand to drop freely during the period of descent.

' 4. In a centrifuging apparatus for preparing raw sand and the like, means for projecting the sand into the atmosphere in a free, unconfined stream in an are having an upward inclination to the horizontal said are being free of any confining surfaces and an -electr0-magnet disposed above the trajectory of said projected sand parti-' to the horizontal said are being free of any confining surfaces and an electro-magnet disposed above the trajectory of said projected sand particles and adjacent the crown thereof whereby the separated sand will fall freely in the descending portion of saidarc.

6. In a centrifuging apparatus for preparing raw sand and the like,.means. for projecting the sand into the atmosphere in a free, unconfined stream in an arc having an upward inclination to the horizontal said are being free ofany confining surfaces and an eiectro-magnet disposed above the trajectory of' said projected sand part.- cles and adjacent the crown thereof and having a plurality of fingers penetrating into the same, whereby the separated sand will fall freely in the descending portion of said are.

HEINRICH WAGNER. 

